The present invention relates to a ribbon cartridge and in particular to a ribbon cartridge holding 1/4" ribbon for replacement for a 1/2" ribbon cartridge.
Currently a popular ribbon cartridge for typewriters, printers and other business machines which include printing mechanisms, is the NEC 3500 series multistrike ribbon cartridge. This ribbon cartridge utilizes a 1/2" ribbon and has a unique construction wherein the printing mechanism first strikes the upper half of the ribbin surface whereupon the ribbon cartridge is removed, turned upside down and modified in its drive mechanism so that the cartridge can now be reused to print on the other half surface of the ribbon.
While this ribbon cartridge in theory operates well, in practice, there are many disadvantages. Firstly, the ribbon cartridge is extremely complex in construction. Secondly, many users are unaware of the fact that the ribbon cartridge can be turned over and thus after the first pass through the ribbon the cartridge is removed and disposed of, thereby wasting half of the ribbon. Furthermore, the cartridge does not reliably wind the take-up spool during the first pass along the ribbon and thus there is an unreliable winding action in the oppostie direction after the ribbon cartridge has been turned over.
In order to eliminate these disadvantages, a prior art cartridge has been proposed which has the same overall thickness as the original manufacturers cartridge, but which uses a 1/4" ribbon which starts at a supply spool, travels through guide arms, angles upwardly across the printing mechanism gap and then returns to a take-up spool which is disposed on top of the supply spool.
This cartridge has the disadvantage that the cartridge housing is unnecessarily bulky, and because the ribbon, as it travels across the gap between the ends of the guide arms, is slightly twisted and thus does not present a reliable impact surface for the printing mechanism.